Multi-layer golf ball having velocity gradient from faster center to slower cover

Abstract

The present invention is directed to multi-layer golf balls having a center, a cover layer, and at least one intermediate layer between the core and the cover layer. The core, the at least one intermediate layer and the cover are constructed to have different initial velocities and COR such that the gradient of the initial velocities and COR progress from a faster center to a slower cover.

1. A multi-layer golf ball comprising a center, a cover layer, and at least two intermediate layers between the center and the cover layer,
 wherein each subassembly of the golf ball has a combined coefficient of restitution value greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.003, 
 wherein the subassembly comprises at least the center, and 
 wherein the center has a coefficient of restitution value of at least 0.815. 
 
   
   
     2. The multi-layer golf ball of  claim 1 , wherein each subassembly has a combined coefficient of restitution value that is greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.005. 
   
   
     3. The multi-layer golf ball of  claim 1 , wherein each subassembly has a combined coefficient of restitution value that is greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.010. 
   
   
     4. The multi-layer golf ball of  claim 1 , wherein the intermediate layers comprises 8 layers or less. 
   
   
     5. The multi-layer golf ball of  claim 1 , wherein the center has a coefficient of restitution value of at least 0.825. 
   
   
     6. The multi-layer golf ball of  claim 1 , wherein the center has a coefficient of restitution value of at least 0.830. 
   
   
     7. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center and the first intermediate layer has a combined coefficient of restitution value of at least 0.810. 
   
   
     8. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center and the first intermediate layer has a combined coefficient of restitution value of at least 0.820. 
   
   
     9. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center and the first intermediate layer has a combined coefficient of restitution value of at least 0.825. 
   
   
     10. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center, the first intermediate layer, and the second intermediate layer has a combined coefficient of restitution value of at least 0.800. 
   
   
     11. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center, the first intermediate layer, and the second intermediate layer has a combined coefficient of restitution value of at least 0.810. 
   
   
     12. The multi-layer golf ball of  claim 1 , wherein the subassembly represented by the center, the first intermediate layer, and the second intermediate layer have a combined coefficient of restitution value of at least 0.815. 
   
   
     13. The multi-layer golf ball of  claim 1 , wherein
 the center comprises a highly neutralized polymer formed from a reaction between acid groups on a polymer, a suitable source of cation, an organic acid or the corresponding salt, and 
 the amount of the suitable source of cation is sufficient to neutralize the acid groups by at least about 80%. 
 
   
   
     14. The multi-layer golf ball of  claim 13 , wherein the amount of the suitable source of cation is sufficient to neutralize the acid groups by about 90%. 
   
   
     15. The multi-layer golf ball of  claim 1 , wherein the center is a product of a reaction mixture comprising a polybutadiene, a cis-to-trans catalyst, a free radical source, a crosslinking agent, and a filler. 
   
   
     16. The multi-layer golf ball of  claim 1 , wherein the at least one intermediate layer comprises a polybutadiene, a polyurethane, a polyurea, a highly neutralized polymer, a silicone, a polyolefin, a polyamide, a polyester, a polyether amide, a polyester amide, or a blend thereof. 
   
   
     17. The multi-layer golf ball of  claim 1 , wherein the cover layer comprises a polyurethane, a polyurea, a highly neutralized polymer, a polybutadiene, a polyolefin, or a blend thereof. 
   
   
     18. A multi-layer golf ball comprising a center, a cover layer, and at least two intermediate layers between the center and the cover layer,
 wherein each subassembly of the golf ball has a combined coefficient of restitution value greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.003; 
 wherein the subassembly comprises at least the center; and 
 wherein the change in coefficient of restitution from one subassembly to the next larger assembly per the thickness of the next larger subassembly is at least 0.00015 per thousandth of an inch. 
 
   
   
     19. The multi-layer golf ball of  claim 18 , wherein said change in coefficient of restitution is at least about 0.00025 per thousandth of an inch. 
   
   
     20. The multi-layer golf ball of  claim 18 , wherein said change in coefficient of restitution is at least about 0.00035 per thousandth of an inch. 
   
   
     21. A multi-layer golf ball comprising a center, a cover layer, and at least two intermediate layers between the center and the cover layer,
 wherein each subassembly of the golf ball has a combined coefficient of restitution value greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.003; 
 wherein the subassembly comprises at least the center; 
 wherein the center comprises a highly neutralized polymer formed from a reaction between acid groups on a polymer, a suitable source of cation, an organic acid or the corresponding salt; the amount of the suitable source of cation is sufficient to neutralize the acid groups by about 100%; the suitable source of cation is selected from the group consisting of magnesium, sodium, zinc, lithium, potassium and calcium; and the organic acid or the corresponding salt is selected from the group consisting of oleic acid, salt of oleic acid, stearic acid, salt of stearic acid, behenic acid, salt of behenic acid and combination thereof. 
 
   
   
     22. A multi-layer golf ball comprising a center, a cover layer, and one intermediate layer between the center and the cover layer,
 wherein each subassembly of the golf ball has a combined coefficient of restitution value that is greater than the combined coefficient of restitution of said subassembly plus the next outer layer by a value of at least 0.004; 
 wherein the subassembly comprises at least the center; and 
 wherein the change in coefficient of restitution from one subassembly to the next larger assembly per the thickness of the next larger subassembly is at least 0.00015 per thousandth of an inch. 
 
   
   
     23. The multi-layer golf ball of  claim 22 , wherein said change in coefficient of restitution is at least about 0.00025 per thousandth of an inch. 
   
   
     24. The multi-layer golf ball of  claim 22 , wherein said change in coefficient of restitution is at least about 0.00035 per thousandth of an inch.